1. Field of the Invention
The present invention relates to an indirect heat exchanger filled with solid-gas reaction powdery particles for exchanging heat with solid-gas reaction powdery particles under an elevated pressure condition.
2. Description of the Related Art
The following literature discloses hydrogen absorbing tanks which are constituted as sealed tanks which include a hydrogen absorbing alloy powder and an indirect heat exchanger and store hydrogen gas by utilizing the hydrogen absorbing-desorbing action of the hydrogen absorbing alloy powder.
The indirect heat exchanger has heat storage medium conduits, a heat-exchanger set having many fins secured to the outer surfaces of the heat storage medium conduits to exchange heat with the hydrogen absorbing alloy powder, an inlet side header joined to the inlet side ends of the heat storage medium conduits, and an outlet side header joined to the outlet side ends of the heat storage medium conduits.
According to Japanese Unexamined Patent Publication (Kokai) No. 6-281097, the heat-exchanger, having the heat storage medium conduits and fins formed as a unitary structure through the metal-extrusion molding, is contained in a casing having a nearly square shape in cross section in a direction at right angles to the direction in which the heat storage medium conduits extend, tenons are formed at the outer ends of the fins, tenon grooves are formed in the inner surfaces of the casing, and the two are joined together by the tenons, so that the casing will not be swollen by the fins.
Japanese Unexamined Patent Publication (Kokai) No. 11-30397 discloses an indirect heat exchanger (hereinafter often referred to as a zigzag-type indirect heat exchanger) in which a heat-exchanger set is constituted by a flat tube (heat storage medium conduit) arranged in a zigzag manner in many stages in the direction of height and holding corrugated fins between the stages, and both ends of the flat tube are joined a pair of headers, respectively. The flat tube includes partitioning walls arranged at a predetermined distance in the direction of width therein, so that the interior of the flat tube is divided into many small flow passages.
Japanese Unexamined Patent Publication (Kokai) No. 7-330301 proposes an indirect heat exchanger (hereinafter often referred to as a parallel shunt-type indirect heat exchanger) in which many flat tubes are arranged in many stages in the direction of height to constitute a heat-exchanger holding corrugated fins, and both ends of the flat tube are separately joined to a pair of headers. The two headers are secured to a closure that closes the opening of a square can body having a bottom which is opened at its upper end.
With the indirect heat exchanger filled with solid-gas reaction powdery particles having the above-mentioned tenon-coupled heat-exchanger set, however, the fins must be formed with a decreased thickness and must be provided in a small number to maintain the volume for containing the hydrogen absorbing alloy powder, resulting in an increase in the heat-conducting resistance between the heat storage medium in the heat storage medium conduits and the hydrogen absorbing alloy powder. Besides, the tenons formed at the outer ends of the fins can be slid and pushed into the tenon grooves formed at the inner surfaces of the casing. This work involves difficulty when it is attempted to decrease the clearance between the two.
In the above-mentioned zigzag-type indirect heat exchanger, the flat tube is set at a right angle to the direction of transfer of the heat storage medium and develops a difference in temperature between the small flow passages, in the direction of transfer. Besides, some small flow passages may be clogged or constricted with the metal powder, spoiling or greatly deteriorating the heat-exchanging function of the small flow passages as a whole.
In the above-mentioned parallel shunt-type indirect heat exchanger, the flat tubes are extended in a horizontal direction to suppress the sedimentation of the hydrogen absorbing alloy powder and, as a result, the headers are extended in the vertical direction. When the casing is constituted by a can body and a closure plate for closing the opening, the headers are generally joined to the closure plate. Accordingly, the closure plate extends in parallel with the flat tubes, and it is not easy to fill the space between the neighboring corrugated fins with the hydrogen absorbing alloy powder to a sufficient degree through the opening in the can body.
Besides, the two headers must be wider than the flat tubes at both ends of the flat tubes. In other words, the headers have large volumes, resulting in a decrease in the volume of the casing that is to be filled with the hydrogen absorbing alloy powder.